JP2001268839A - Spindle motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new stopper structure providing no problem such as noise, iron loss, size and price in a spindle motor including a dynamic pressure fluid bearing mechanism. SOLUTION: There are provided a fixed shaft 11 and a rotating sleeve 22 which are engaged with each other to form a dynamic pressure fluid bearing mechanism, and an engaging flange 31 and an engaging hook 41 which are provided opposed with each other on the non-contact basis in the axial direction to form a stopper mechanism. The engaging hook 41 includes an elastic part 41c and an introducing slope 41b which are placed in contact with the engaging flange 31 to elastically draws back, the engaging flange 31 is formed at the external circumferential side of the sleeve 22, and the engaging hook 41 is placed at the fixed position in the external circumferential side of the engaging flange 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor having a hydrodynamic bearing mechanism, and more particularly, to a retaining structure for the spindle motor.

[0002]

2. Description of the Related Art Spindle motors having a hydrodynamic bearing mechanism are widely used in equipment requiring precise and high-speed rotation. Among them, it is common to use air as the fluid particularly in high-speed rotating equipment. In air bearings, the bearing diameter is increased to increase the load capacity. Since the shaft is generally made of ferrous metal and is often heavy, the shaft should be fixed rather than rotating. In this manner, the dynamic pressure gas bearing mechanism often has a shaft fixing structure. This fluid bearing mechanism is particularly precise, and the bearing gap is very small, so that entry of dust and the like is prohibited. It is therefore desirable that the motor be assembled in a clean room and not be easily disassembled in the subsequent daily space.

A technique for meeting such a demand is disclosed in Japanese Patent Application Laid-Open No. H10-69713. FIG. 4 shows the structure. In a fixed-shaft type hydrodynamic bearing, a rotor is prevented from falling off by magnetic attraction between a stator and a rotor. Fixed shaft 91 and rotating sleeve 9
2 constitute a radial dynamic pressure bearing, and the magnet 93 and the stator 94 generate a magnetic attraction force to hold the rotor 95.

[0004] Other types of retaining structure include a structure in which a groove is provided at the end of the shaft to engage a stopper, and a structure in which the stopper is supported at one point on the outer periphery of the rotor. A magnetic attraction method is preferred. Since there is no engaging part inside the bearing, there is no problem of foreign matter due to sliding, the bearing structure is simple and it is easy to secure parts processing accuracy, it can be easily attached and detached in the assembly process, and magnetic suction is performed around the entire circumference This is because there is an advantage that no tilt moment is generated.

[0005] However, this magnetic attraction method has disadvantages. First, when a multi-pole magnetized magnet is used to generate a driving magnetic field, vibration noise generated by a high-frequency alternating magnetic field is inevitable. At the same time, iron loss increases. In particular, in the case of a structure using a stator core having salient poles and magnets radially opposed to each other, when these are shifted in the axial direction to generate a magnetic attractive force, the vibration noise is said to be proportional to the magnetic attractive force. It becomes a troublesome problem.

In order to obtain magnetic attraction without increasing vibration noise and iron loss, a magnet that does not have multipolar magnetization in the rotating direction may be used. However, in this method, since a driving magnetic field cannot be generated by a magnet, it is necessary to separately prepare a driving magnetic field, and disadvantages such as an increase in motor size, complexity, and an increase in cost arise.

[0007]

As described above, the magnetic attraction type retaining mechanism used in the spindle motor having the hydrodynamic bearing mechanism has problems in terms of noise, iron loss, dimensions, price, and the like. There was a desire for improvement. Therefore, the present invention has no internal foreign matter, good processing accuracy,
It is an object of the present invention to provide a new retaining structure which has an advantage that it can be detached in a process and does not cause the above-mentioned problems.

[0008]

In order to solve the above-mentioned problems, a spindle motor according to the present invention comprises a fixed shaft and a rotating sleeve which are fitted to each other to form a hydrodynamic bearing mechanism. An engaging flange and an engaging hook, which constitute a retaining mechanism in non-contact with the engaging flange, and the engaging hook has an elastic portion and an introduction slope for abutting against the engaging flange and elastically retracting. The engaging flange is formed on the outer peripheral side of the sleeve, and the engaging hook is fixedly arranged on the outer peripheral side of the engaging flange.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 of the present invention is characterized in that: a) they are fitted together to form a hydrodynamic bearing mechanism;
A fixed shaft and a rotating sleeve; and b) an engaging flange and an engaging hook which face each other in an axially non-contact manner to constitute a retaining mechanism, and c) the engaging hook is attached to the engaging flange. A spindle motor having an elastic portion for elastically retracting in contact with it, d) an engaging flange formed on the outer peripheral side of the sleeve, and an engaging hook fixedly arranged on the outer peripheral side of the engaging flange.

Thus, in the fixed shaft type bearing mechanism,
The retaining mechanism comprises an engaging flange and an engaging hook. While adopting a structure different from the conventional magnetic attraction method, a retaining mechanism having advantages such as no internal foreign matter, good processing accuracy, and detachability in a process is configured. In addition, a motor that does not generate noise, vibration, and magnetic loss and has a simple structure is realized. In addition, since the engagement hook has a structure in which the engagement hook is elastically retracted by contacting the engagement flange, the engagement is performed only by fitting the sleeve, and a motor having good assembling workability can be realized. Since the engagement flange and the engagement hook are formed on the outer peripheral side of the sleeve, the height of the motor can be reduced without losing the length of the sleeve.

According to a second aspect of the present invention, there is provided a) a fixed shaft and a rotating sleeve which are fitted to each other to form a hydrodynamic bearing mechanism, and b) are opposed to each other in an axially non-contact manner. An engaging flange and an engaging hook that constitute a retaining mechanism; and c) a stator core that is disposed on an outer periphery of the bearing mechanism and that drives the rotor to rotate. D) The engaging hook abuts on the engaging flange and is elastic. E) an engaging flange is integrally formed on the outer peripheral side of the sleeve, and the engaging hook is fixedly arranged on the outer peripheral side of the engaging flange and the inner peripheral side of the stator core. It is a spindle motor.

Thus, in the fixed shaft type bearing mechanism,
A retaining mechanism is arranged with a gap provided on the inner peripheral side of the stator core. Since the inner peripheral side of the core has a small radius and a small contribution to the motor output, the motor volume does not increase due to the addition of the retaining mechanism. The engagement of the retaining mechanism is held immediately near the bearing. Therefore, the load in the moment direction is not applied to the bearing, and the damage to the bearing can be reduced as compared with the retaining mechanism of the single-point support structure to which the moment load is applied.

The engaging hook has an elastic portion and an introduction slope. Due to the introduction slope, the load when inserting the shaft and the rotor can be reduced, and the shaft and the rotor are not damaged such as scratches. Further, since the engagement flange is formed integrally with the outer peripheral side of the sleeve, the engagement flange can be made strong and can be easily formed.

According to a third aspect of the present invention, there is provided the spindle motor according to the first or second aspect, wherein a plurality of engagement hooks are arranged substantially equally around the engagement flange. The plurality of engaging hooks uniformly hold the periphery of the engaging flange. In addition, the engagement is maintained immediately adjacent to the bearing. Therefore, no load in the moment direction is applied to the bearing,
Damage to the bearing can be reduced as compared with the retaining mechanism of the one-point support structure to which a moment load is applied. Furthermore, since no force is applied to the outer periphery of the rotor, no distortion occurs in the rotor, and no imbalance occurs.

According to a fourth aspect of the present invention, a ring-shaped support portion, in which a groove is formed partially so as to be able to reduce the diameter, is formed integrally with the engagement hook, and the support portion is formed on the inner peripheral side of the stator core. 3. The spindle motor according to claim 2, wherein said spindle motor is housed and held in said recess. Since the ring-shaped support portion can be snap-fitted to the concave portion formed on the inner peripheral side of the stator core, the engaging hook can be easily mounted when assembling the motor, and the assembling workability is improved.

According to a fifth aspect of the present invention, there is provided the spindle motor according to the first or second aspect, wherein the engagement hook is formed of a resin material. Damage such as damage due to the contact between the engaging hook and the engaging flange can be minimized, and the generation of foreign matter can be prevented.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a structural sectional view of a spindle motor according to one embodiment of the present invention. FIG. 2 is a perspective view of the stopper (engaging hook). FIG. 3 is a schematic diagram for explaining the relationship between the detailed shape of the engagement hook and the engagement flange and the assembly disassembly.

In FIG. 1, the spindle motor is formed as a drive source for driving the polygon mirror 51 to rotate at high speed. The bearing is a hydrodynamic bearing mechanism, and the radial bearing portion is composed of a fixed cylindrical shaft 11 and a sleeve 22 that surrounds and rotates around the shaft. A dynamic pressure generating groove is formed in any of them. The thrust bearing is a rigid flat plate 1 embedded in the end face of the shaft.
2 and a resin spherical plate 23 opposed thereto.

The motor is divided into a stator (all of the fixed members) and a rotor (all of the rotating members).
Around the shaft 11, a bracket 13 for supporting the shaft 11,
It is composed of a shaft mounting screw 14 for the connection, a metal substrate 15 for mounting the bracket to the device, a stator assembly fixed to the bracket and driving the rotor to rotate. The stator assembly is performed by winding the winding 17 around the stator core 16.
The inner circumference of the stator core is supported by brackets 13.

On the other hand, the rotor is constructed around a rotor frame 21. The sleeve 22 is a cylindrical portion formed on a part of the rotor frame and surrounding the shaft to form a bearing.
At the end of the rotor frame, there is a thrust cover 24 for holding the resin spherical plate 23 described above. A multi-pole magnetized magnet 25 is fixed inside the rotor frame at a position facing the stator assembly. A polygon mirror 51 is mounted on the upper part of the rotor frame, and a mirror retainer 52 is mounted on the polygon mirror 51 and fixed with a mirror fixing screw 53. When the winding 17 of the motor configured as described above is externally supplied with power and driven, the rotor rotates.

The retaining mechanism is formed as an engagement structure on the inner peripheral side of the stator core. Please refer to FIG. 1 for the relationship with the entire motor, FIG. 2 for the shape of the stopper (engaging hook), and FIG. 3 for details. The rotating side of the mechanism
An engagement flange 31 is integrally formed on the outer peripheral surface of the sleeve 22 of the rotor frame 21. The engagement flange has an engagement surface 31a and an introduction slope 31b as shown in FIG. 3, and has a conical shape as a whole. The engagement flange is formed within an axial range of a radial bearing portion for supporting a radial load.
The other fixed side is a key-shaped fixing member that faces the engaging flange in the axial direction, and is referred to as an engaging hook. As shown in FIG. 2, there are three engaging hooks 41, which equally surround the periphery of the engaging flange 31. The three engagement hooks 41 are held by a ring-shaped support portion 42. This member is referred to as a stopper 40 as a whole. The stopper is made of resin and is elastically deformable.
The ring-shaped support member 42 of the stopper is housed in a recess provided in the bracket as shown in FIG. For this reason, the ring-shaped support portion has a part of its circumference cut out so that its diameter can be reduced.

When assembling the motor, the stator and the rotor are separately assembled. In the stator, the stopper 40 described above is fitted into the bracket 13 and the shaft 11 and the sleeve 22 are fitted slowly. When the sleeve is inserted, the engagement flange 31 is engaged with the engagement hook 4.
1, the engaging hook is elastically retracted and further enters, and the fitting of the bearing and the engagement of the retaining mechanism are completed at the same time. After assembling in this manner, careless disassembly can be prevented by the function of the retaining mechanism.

As described above, in the motor according to the present embodiment, the retaining mechanism is constituted by the engaging flange 31 and the engaging hook 41 in the fixed shaft type bearing mechanism. No conventional magnetic thrust force or suction magnet is used to prevent the cap from coming off. Therefore, there is no vibration and noise caused by using the magnetic thrust force. There is no iron loss due to the alternating magnetic field. Alternatively, there are no drawbacks such as an increase in motor size, a complicated structure, and a high price due to the addition of a suction magnet.

The engaging hook 41 is connected to the engaging flange 3.
Since the sleeve 1 is elastically retracted by contacting the sleeve 1, the engagement is achieved only by fitting the sleeve, and the assembly is easy.
Since the engaging flange and the engaging hook are formed on the outer peripheral side of the sleeve, compared with the case where the retaining mechanism is formed in series with the bearing mechanism, such as forming a retaining groove at the tip of the shaft,
No loss of sleeve length. Therefore, the motor height can be reduced.

Further, since the engagement flange is formed within the axial range of the radial bearing portion, even if a radial load is generated due to the asymmetry of the retaining mechanism, the load is within the support range of the radial bearing. No large moment load is applied to Therefore, damage to the bearing can be reduced.

The motor according to the present embodiment has a stator core 1
An engagement hook 41 is arranged on the inner circumference of the bracket 13 that holds the inner circumference of the bracket 6. That is, the retaining mechanism is disposed in the gap provided on the inner peripheral side of the stator core. Since the inner peripheral side of the core is a portion having a small radius and a small contribution to the motor output, providing the retaining mechanism in this portion does not greatly increase the motor volume. Further, the engagement of the retaining mechanism is performed immediately near the bearing. Therefore, the load in the moment direction is not applied to the bearing, and the damage to the bearing can be reduced as compared with the retaining mechanism of the single-point support structure to which the moment load is applied. Compared to the conventional structure in which the retaining mechanism is provided on the outer periphery of the rotor, distortion does not occur on the outer periphery of the rotor, so that unbalance can be eliminated.

The engaging hook 41 has an elastic portion 41c and an introduction slope 41b. Due to the presence of this introduction slope,
The load when inserting the shaft and the rotor can be reduced.
Therefore, no damage such as a scratch is given to the shaft / rotor. Further, since the engagement flange 31 is formed integrally with the outer peripheral side of the sleeve 22, the engagement flange can be made strong and can be easily formed.

Further, in the motor of the present embodiment, three engaging hooks are arranged at equal intervals of 120 ° around the engaging flange. With this configuration, the entire circumference of the engagement flange can be supported with a uniform force, and the occurrence of a load in the moment direction due to unevenness can be prevented. Therefore, damage to the bearing can be reduced.

In the motor of this embodiment, a notch (groove) is provided in a part so that the diameter of the ring-shaped support portion 42 of the stopper 40 can be reduced. The ring-shaped support portion is housed and held in a recess formed on the inner peripheral side of the stator core. Since the engaging hook is configured to be easily assembled, a motor with high productivity can be obtained. In the motor of this embodiment, the engagement hook is formed of a resin material. Even during contact, the generation of foreign matter can be prevented by minimizing damage such as scratches.

Here, the detailed shapes of the engagement hook and the engagement flange will be described with reference to FIG. The retaining mechanism for the motor according to the present embodiment is made not only easy to assemble but also disassembled. The parameters related thereto include the length of the elastic portion, the elastic force (flexural rigidity), the angle of the introduction slope, the angle of the engagement surface, and the like for the engagement hook. In the case of the engagement flange, the angle of the introduction slope, the angle of the engagement surface, and the like are used.

In the drawing, when the engagement hook 41 and the engagement flange 31 are inserted and engaged, each of the introduction slopes 4 is engaged.
1b and 31b contact. The force required for insertion varies depending on the positional relationship between the two, but in most cases is determined by the inclination angle of the gentler inclination. In this embodiment, the introduction inclination angle θf of the engagement flange is larger than the introduction inclination angle θhi of the engagement hook.
Since i is small, it is determined on the engagement flange side. The force by which the engaging hook is elastically retracted is the base point 41 of the elastic portion of the engaging hook.
Although it is reasonable to discuss the angle with respect to d, simply expressing the angle with respect to the axis Z, the introduction inclination angles θhi and θfi with respect to the axis of the engagement hook or the engagement flange are 45 °.
It is better to do the following. At this time, the insertion engagement is performed favorably, and the shaft rotor is not damaged such as a scratch.

On the other hand, when the engagement hook is disengaged from the engagement flange and disassembled, the respective engagement surfaces 41a, 3a
1a contacts. The force required for disengagement is basically determined by the inclination angle of the gentler inclination. In this embodiment, since the engagement inclination angle θh of the engagement hook is smaller than the engagement inclination angle θf of the engagement flange, it is determined on the engagement hook side.
In this case as well, it is reasonable to discuss the retreating force of the engaging hook in terms of the angle viewed from the base point 41d of the elastic portion of the engaging hook. Engagement inclination angles θh, θf with respect to the axis of the mating flange
Is preferably 70 to 85 °. With this range,
It was possible to achieve both an impact resistance of 980 m / s2 (100 G) and good decomposability.

In order to obtain an irreversible structure that is difficult to decompose,
In the engagement hook (and the engagement flange), the engagement surface viewed from the base of the elastic portion may be configured such that the distance M to the inner diameter side is equal to or greater than the distance N to the outer diameter side. In such a case, the component force of the force generated on the engagement surface does not face the direction for retracting the engagement hook. Therefore, it cannot be disassembled without applying force that causes destruction.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various applications and developments can be made within the scope of the present invention.

[0036]

As described above, according to the present invention, there is no internal foreign matter, good processing accuracy, while overcoming the disadvantages of the conventional structure such as vibration, noise, load loss, enlargement, and complexity. It is possible to provide a new retaining structure having an advantage that it can be detached in a process.

[Brief description of the drawings]

FIG. 1 is a structural sectional view of a spindle motor according to an embodiment of the present invention.

FIG. 2 is a perspective view of a stopper (engaging hook) of the spindle motor according to one embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating a relationship between a detailed shape of an engaging hook and an engaging flange of the spindle motor and an assembling / disassembling property according to one embodiment of the present invention.

FIG. 4 is a structural sectional view of a spindle motor according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Shaft 13 Bracket 16 Stator core 21 Rotor frame 22 Sleeve 25 Magnet 31 Engagement flange 31a Engagement surface 31b Introduction slope 40 Stopper 41 Engagement hook 41a Engagement surface 41b Introduction slope 41c Elastic part 42 Ring-shaped support part

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takao Yoshitsugu 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F term (reference) 5H019 AA06 CC04 DD01 EE14 FF03 5H605 AA04 AA05 AA07 BB05 BB19 CC03 EA06 EA09 EB09 EB38 FF06 GG04 5H607 AA12 BB01 BB09 BB14 BB17 GG12 5H621 BB07 GA01 JK01 JK08

Claims (5)

[Claims] A fixed shaft and a rotating sleeve that fit together to form a hydrodynamic bearing mechanism;
An engagement flange and an engagement hook are provided to oppose each other in a non-contact manner in the axial direction, and an engagement flange and an engagement hook are provided.The engagement hook has an elastic portion for abutting against the engagement flange and elastically retracting. A spindle motor having the engaging flange formed on the outer peripheral side of the sleeve and the engaging hook fixedly arranged on the outer peripheral side of the engaging flange. 2. A fixed shaft and a rotating sleeve that fit together to form a hydrodynamic bearing mechanism;
An engaging flange and an engaging hook that face each other in a non-contact manner in the axial direction to form a retaining mechanism, and a stator core that is disposed on the outer periphery of the bearing mechanism and that rotationally drives a rotor, wherein the engaging hook is An elastic portion and an introduction slope are provided to abut on the engaging flange and retreat elastically, and the engaging flange is integrally formed on an outer peripheral side of the sleeve,
A spindle motor in which the engaging hooks are fixedly arranged on an outer peripheral side of the engaging flange and on an inner peripheral side of the stator core. 3. The spindle motor according to claim 1, wherein a plurality of engaging hooks are arranged substantially equally around the engaging flange. 4. A ring-shaped support portion having a groove partially formed therein so as to be able to reduce the diameter is formed integrally with the engagement hook, and the support portion is housed and held in a concave portion formed on the inner peripheral side of the stator core. Item 6. The spindle motor according to Item 2. 5. The spindle motor according to claim 1, wherein the engagement hook is formed of a resin material.